Abstract

MARTOS, Maria Alicia; BUTIUK, Ana Paula; ROJAS, Natalia Lorena  and  HOURS, Roque Alberto. Batch culture of Wickerhamomyces anomaìus in a lab scale bioreactor for poligalacturonase production. Rev. colomb. biotecnol [online]. 2014, vol.16, n.2, pp.68-73. ISSN 0123-3475.  https://doi.org/10.15446/rev.colomb.biote.v16n2.47245.

Wickerhamomyces anomalus, a yeast isolated from citrus fruit peels in the province of Misiones, Argentina, produces a polygalacturonase (endo-PG) with maceration activity of vegetable tissues. The objective of the present work was to determine kinetic and stoichiometric parameters of W. anomalus growth and polygalacturonase production in a synthetic culture medium, operating in a batch-type bioreactor at laboratory scale. Cultures were performed in a bioreactor of 4 l, containing 3 l of a synthetic medium composed of glucose, citrus pectin, vitamins, amino acids, ammonium sulfate and salts, and were incubated with agitation (450 rpm) and aeration at 30 °C, during 12 h. The course of the fermentation process was followed by measuring biomass, residual glucose, polygalacturonase activity and O₂ and CO₂ content of outlet gases from the reactor. The maximum specific growth rate (Um) of W. anomalus was 0.337 h-1 and the biomass yield (Y_x/s) was 0.40 gx/gs. At the end of the culture, PG activity in the supernatant was ~84 UE/ml. The specific activity and the productivity obtained were ~1.91 104 UE/gx and ~9,301 UE/l.h, respectively. Respiratory quotient was approximately 1.0 throughout the fermentation process. No other product different from biomass and CO₂ was detected. Batch culture could be an adequate alternative for the production of polygalacturonase from W. anomalus and an extract with high enzymatic activity using a synthetic and economic culture medium could be obtained.

Keywords : Wickerhamomyces anomalus; polygalacturonase; batch culture; kinetic parameters; stoichiometric parameters.

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